The objective of this Workstatement is to explore several mechanistic classes using a select number of agents known to belong to that class. The following assays are being used: (1) Aromatase inhibitors using human placenta as a source of aromatase (2) Antioxidants (2) Apoptosis inducers using HL60 cells, propidium iodide and flow cytometry (3) Epidermal Growth Factor Receptor (EGFR) Tyrosine Kinase Inhibitors using NIH3T3 cells (4) Differentiation modulators using HL6O cells (5) DHEA Derivatives using glucose-6-phosphate as a substrate. There are five agents in each mechanistic category to measure.